In golf ball design, aerodynamic flight is achieved through spin. All golf shots (except for topped shots and some players' putts) feature Backspin. This means that as the ball flies towards the target, the top of the golf ball is rotating away from the target as the bottom of the ball is rotating towards the target. This creates a phenomenon where the air molecules traveling over the top half of the ball move faster than the air molecules traveling over the bottom half of the ball. The slower moving molecules under the ball are more closely packed and thus denser than the faster-moving, less dense air molecules above the ball.
This warping of the airflow pattern results in a pressure imbalance which exerts an upward force in a direction perpendicular to the line of flight and the axis of the ball's rotation. This force is known as Lift.